Today in United States v. Marinello, the U.S. Supreme Court resolved a circuit split and significantly narrowed the reach of Internal Revenue Code Section 7212(a)'s Omnibus Clause, which makes it a felony to "corruptly or by force...endeavor[r] to obstruct or imped[e] the due administration of this title [the Internal Revenue Code]."

The Court held that the phrase "'due administration of [the Tax Code]' does not cover routine administrative procedures that are near-universally applied to all taxpayers, such as the ordinary processing of tax returns. Rather the clause as a whole refers to specific interference with targeted governmental tax-related proceedings, such as a particular investigation or audit."

Justice Breyer wrote the 7-2 opinion for the Court. Justice Thomas, joined by Justice Alito, dissented.

The majority relied in part on analogous cases from its general obstruction jurisprudence, including United States v. Aguilar and Arthur Andersen v. United States. Although the focus was on the nexus required between the obstruction and a particular act of administration, the Court also stressed the rule of lenity and the need to provide fair warning to the public. This approach could be potentially relevant to any obstruction of justice case that Special Counsel Mueller may one day bring against President Trump or administration officials. Some of the theories floating around cable television about what constitutes obstruction under the federal criminal code are unusually broad and unlikely to survive rigorous analysis based on Aguilar and Arthur Andersen.